You don't need to sub to Dish Network locals to get EPG data for OTA DTV stations on the 811, right now! (could always change)
Quirks? It's a Dish Network receiver, of course it has some quirks, however, my 811 seems to work fairly stable now, if this 811 has been disconnected since December, you may or may not be getting 287, (which is the latest right now) I don't think it still has gone wide spread, and therefore you may or may not get it. You should be at 284 right now, which is fairly stable, (best since I got my 811! including 287!!!). Besides that, there really isn't that much, if it is 284 and it doens't update to 287 then you can only store 120 channels between all four favorite lists, most of the DIsh Home apps are there, and generally it works fine. There is some issues with using recall between ota and satellite channels. Beyond that, it is a typical Dish Network receiver.
Of course, you could have problems that no one else has! But I don't think you will see that big of a difference as far as quirks go between the 6000 and the 811. I have to 301's and they do pretty much the same kind of things as my 811 does. (EPG problems, etc...)